The present invention relates to a novel process for the preparation of mixtures of compounds which mixtures give rise to an intense sandalwood aroma, products produced by said process, perfume compositions containing the product of such process, perfumed articles containing the product of such process and colognes containing the product of such process.
In perfumery, perhaps the most desired of the popular wood notes, as well as the most expensive and least available, is the sandalwood odor. Oil of sandalwood, therefore, while being highly prized in the perfume world because of its desirable odor, has enjoyed only limited use, on account of its limited availability and high cost.
In the past, efforts have been made to produce synthetic substitutes for the natural oil of sandalwood, but they have met with limited success. One of the products heretofore known is the chemical, 1-oxy-2-methoxy-4-camphylcyclohexane, also sometimes referred to as isobornylhexahydroguaiacol, which is described in German Pat. No. 876,241. The formula of the aforementioned compound may be represented as follows: ##STR1## Certain Russian workers, in 1957, published an industrial method for the manufacture of this compound, isobornylhexahydroguaiacol, which they termed, Santalidol, and described it as having a fairly mild odor of the sandalwood type. L. A. Kheifits et al., Masloboino-Zhirovaya Prom 23, No. 6, 35-38 (1957); Chem. Abs., 51, 17, 107.sup.d (1957).
The process employed by Kheifits et al involves the hydrogenation of isobornylguaiacol and isomers thereof in the presence of Raney nickel at elevated temperature and pressure.
Dorsky and Easter in U.S. Pat. No. 3,499,937, issued on Mar. 10, 1970 modified the Kheifits et al process to increase the amount of hydrogen absorbed by the isobornylguaiacol and isomers thereof. The increased amount of hydrogen apparently altered the chemical nature of the product and instead of isobornylhexahydroguaiacol and isomers thereof, which contains one hydroxyl and one methoxyl group, Dorsky and Easter indicated that they formed a new polycyclic alcohol having the formula C.sub.16 H.sub.28 O which has one hydroxyl and no methoxyl group. The methoxyl group apparently was removed by hydrogenolysis. Dorsky and Easter reported that the process of U.S. Pat. No. 3,499,937 created a material possessing a strong, sandalwood-type odor. U.S. Pat. No. 3,499,937 stated that the polycyclic alcohol thus prepared is a viscous, colorless oil with a strong sandalwood-type odor having the formula: ##STR2## In accordance with the Dorsky and Easter process, a material is hydrogenated having the formula: ##STR3## where R is a lower aliphatic hydrocarbon radical having up to 5 carbon atoms, an aromatic or a cycloaliphatic hydrocarbon radical having up to 2 carbon atoms in the side chain, in the presence of a nickel hydrogenating catalyst or copper chromite at an elevated temperature and pressure, until at least 3.5 moles of hydrogen per mole of said material have been absorbed.
At column 3, lines 35-40 Dorsky and Easter state that temperatures between about 140.degree. and 250.degree. C, and pressures above 250 pounds per square inch give satisfactory results, but that preferably temperatures within the range of 175.degree. C and 200.degree. C and pressures of from about 400 up to about 1000 pounds per square inch are used.
Swiss Pat. No. 423,058 (Demole), issued on Apr. 29, 1967, teaches that the odor of the mixture of isomers having the structure: ##STR4## is due to a stereoisomer having the configuration: ##STR5## The above-mentioned stereoisomer is taught to be prepared by condensing phenol with camphene in the presence of boron trifluoride at a temperature of 100.degree. C to form a terpenyl phenol mixture; then treating the terpenyl phenol mixture with ozone thus forming a mixture of terpenyl carboxylic acids; purifying the mixture of terpenyl carboxylic acids and then carrying out a complicated sequence of reaction steps forming the desired stereoisomer product, to wit:
1. Preparation of a Terphenyl Methyl Ketone Mixture;
2. Preparation of an Enamine of Trimethyl-2,2,3-Norbornyl-5-methyl ketone;
3. Preparation of Trimethyl-2,2,3-norbornyl-5-)-3-cyclohexene-2-one-1;
4. Preparation of (trimethyl-2,2,3-norbornyl-5-)-3-cyclohexenol-1; and
5. Separation of the Stereoisomer Resulting Therefrom.
However, neither the Demole Patent nor the Dorsky and Easter Patent disclose a technique for preparing the intensely powerful sandalwood material of the instant invention.
In addition, neither the Demole nor the Dorsky or Easter Patent disclose the preparation of the intermediate diol isomer mixture having the structure: ##STR6##